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To the best of my knowledge Polyphony Digital had nothing to do with the little gizmo that entertained me all the way home and back in last night’s Chevy Cobalt SS. The turbo-direct-injected 2.0-liter engine comes standard with an analogue boost gauge, mounted on the A-pillar (as SEMA intended). But for $295, you can replace that dull one-trick needle with a small display screen that emulates the look of the analogue gauge, but is reconfigurable.

Naturally it will indicate boost, both with a needle and with a digital readout below, and with a display that also tells you what gear you’re in, both digitally and with a little red shift-knob (deduced by the engine controller comparing engine and vehicle speed–it doesn’t read out until you’re moving with the clutch fully engaged).

There’s also a handy power/torque meter that reads power with the analogue needle and torque in the digital readout. I believe this is strictly based on computations made by the engine controller, so it’s unclear to me whether the benefit gained by certain aftermarket tweaks would show up here and save you a trip to the dyno. In this shot you’ll also notice that the gear-indicator gizmo also an upshift indicator with a tall arrow that illuminates green, yellow, red as you approach redline. This is quite useful, as it’s clearly noticeable in your peripheral vision.

Utilizing Stabilitrak’s gyro sensors, there’s a screen that reads out a large digital speed display as well as a bar graph and digital readout of lateral acceleration left or right, and keeps track of your peak readings in either direction.

From here the displays get pretty esoteric. Like cam phaser position. Two needles sweep the analogue dial to indicate the relative advance of the exhaust and intake cams and the digital display indicates total overlap. There’s zero overlap (both are at 0 degrees) at idle. Under light-load cruising conditions the overlap maxes out at between 80 and 90 degrees (roughly 40-45 degrees on each cam). Mid-throttle openings show more like 40 degrees of overlap and at wide-open I saw about 35 degrees.

Did you ever wonder how much spark advance you were running? Me neither, but apparently in DI turbo Chevy‘s it’s zero at idle, 5-10 degrees under hard acceleration, and as high as 40 degrees under light-load cruising conditions. Another info item that appears on this screen is a warning light alerting you when the traction control is active. And interestingly enough, when it’s blinking, you can see the spark retarding to bring wheel-spin under control. On this display, the digital readout is dedicated to “knock retard degrees,” which presumably only flashes a number when low-octane fuel or high altitude operation causes the knock sensors to register preignition, prompting a retarding of the spark.

Perhaps the most arcane info displayed is real-time air-fuel ratio, which deviates from the stoichiometric 14.7:1 air:fuel mass ratio than I’d have thought. While cruising along, the needle dithers near that figure. Floor it, and it goes rich (to maybe 12:1 or so). Suddenly lift and it also goes momentarily rich and then full lean. The readout maxes at 18:1, but if it uses full fuel shut-off it’s more like infinite. Okay, I probably wouldn’t look at this screen much, but several of these screens could keep me entertained for perhaps the length of the lease. Well done.